In general, the present invention relates to the field of keypads, more particularly, to a keypad that is used with an electronic device to input information and/or commands to the electronic device.
Keypads for inputting information and/or commands into electronic devices are well known. For example, telephone-type keypads are well known for telephones of the corded, cordless and wireless types of telephones. These telephone keypads typically have twelve buttons, corresponding to each of the ten single digits as well as the * (star) and # (pound) symbols. Known telephone keypads can have alphabetic letters assigned to the number keys, and it is possible to enter alphabetic information using these keys. In one known arrangement, three letters are assigned to each of several number keys, and pressing the same number key more than once selects the letter. For example, if the number two (2) key is assigned the letters A, B, and C, then when in an alphabetic mode, pressing the number two key once will select letter A, pressing it a second time will select the letter B, and pressing it a third time will select the letter C. This arrangement has been used to allow a telephone keypad to be able to enter both numeric and alphabetic information into a telephone. An advantage of this arrangement is that a small number of keys, such as only twelve keys, is required. In situations where the space available for the keypad is small, such as a portable cordless or wireless (e.g., cellular) telephone, it is possible to use this arrangement to make each of the keys relatively large with respect to the small area that is available for the keypad. In portable telephones such as cordless or wireless (e.g., cellular) telephones, it is often desirable to make the telephone, and hence the keypad area, compact. Having fewer keys permits each key to be larger and still fit the compact space. However, for text (alphabetic) entry, the need to hit keys multiple times is a disadvantage, because of the requirement for a complex data-entry user-interface.
Another type of keypad used to input information and/or commands into an electronic device is the alphabetic-type keypad. One example of such a keypad is the so-called xe2x80x9cQWERTYxe2x80x9d keypad, which has one key assigned to each of the letters of the alphabet. Such a keypad may also have separate keys for the ten single number digits, and for additional command functions. These keypads provide the advantage of a simple data-entry user-interface in that only one keystroke is required to enter each letter. However, these keypads suffer the disadvantage that at least twenty-six keys are required. If this number of keys is to be fit into a compact space, such as the compact space on a portable telephone, the keys will likely need to be smaller than the keys that could be fit on the same space using the telephone keypad described above. These smaller keys may be less convenient to operate due to their size in circumstances where only numeric entry (such as telephone dialing) is being performed.
When using many electronic devices, a user may sometimes desire to have fewer, larger keys (e.g., when primarily making telephone calls from a cordless or wireless phone) and may at other times desire a greater number of keys (e.g., an alphabetic keypad when entering larger amounts of text data into the wireless telephone or other electronic device). Accordingly, there exists a need to provide an improved keypad that is adaptable between different configurations while still occupying a limited space.